Kalbar Conversations Column

Exploration Drilling 101

   Tuesday 11th August, 2020

In the coming months, Kalbar Operations is planning to undertake further exploratory drilling on the Fingerboards Mineral Sand deposit. Kalbar conducts its exploration drilling under licence in accordance with Earth Resources Regulation (ERR) guidelines. ERR is the government department that regulates the resource industry in Victoria.

Kalbar’s drilling falls into two categories – either ‘Low Impact Exploration’ or under an ‘Area workplan’. We need to inform ERR of where we intend to drill each hole. This is known as a work schedule. When drilling on private land, Kalbar also needs the written consent of the landowner.

Kalbar has extensively drilled the Glenaladale deposit, but we want to undertake further resource drilling to get a sharper picture of our geological model. It’s akin to your high definition TV – the greater the number of pixels, the crisper and clearer the image. By increasing the density of our drilling and assays, we get a better resolution of our geological model.

For resource drilling, Kalbar typically uses ‘aircore’ drilling as it’s efficient. Aircore drilling uses compressed air to lift the sand from the cutting face of the drill bit up through the centre of the rods and out through a cyclone where the air is depressurised and the sample collected. A sample is taken every metre, geologically logged, and sent to a laboratory for analysis. Kalbar uses field duplicates, laboratory duplicates and standardised samples to ensure the veracity of the data.

Kalbar also uses sonic drilling. This technique utilises ultrasonic vibrations with slow rotation to cut through the ground. Although this type of drilling is slower going, and more costly, the sample is more intact. Sonic has ability to drill up to seven-inch (in diameter) core. We normally use sonic drilling to obtain larger samples for metallurgical test work.

Triple tube diamond drilling is another technique we use more sparingly. This uses the rotation of a diamond tipped drill bit to cut through the ground. A casing is installed over the top of the drill rods, then the core barrel is removed from the hole. Core is bought to the surface undisturbed. This technique is ideal for obtaining geotechnical information to inform mine design, and attributes such as shear strength, permeability and density become obvious by analysing the core sample.

Each of these methods of drilling is classified as narrow diameter drilling – which means there is minimal impact on the site on completion. Each drill hole is sealed and topsoil is returned. Typically, a few weeks after drilling, it is hard to distinguish the drill site from the surrounding ground.

If you would like to learn more about our field activities, please call 1800 791 396 or email us at contactus@fingerboardsproject.com.au - we will happily answer any queries.

Kalbar Operations Pty Ltd

Matt Golovanoff - Geologist